From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
MPX is being removed from the kernel due to a lack of support
in the toolchain going forward (gcc).
The first thing we need to do is remove the userspace-visible
ABIs so that applications will stop using it. The most visible
one are the enable/disable prctl()s. Remove them first.
This is the most minimal and least invasive patch needed to
start removing MPX.
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
---
include/uapi/linux/prctl.h | 2 +-
kernel/sys.c | 16 ++--------------
2 files changed, 3 insertions(+), 15 deletions(-)
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index b4875a9..78fcee3 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -181,7 +181,7 @@ struct prctl_mm_map {
#define PR_GET_THP_DISABLE 42
/*
- * Tell the kernel to start/stop helping userspace manage bounds tables.
+ * No longer implemented, but left here to ensure the numbers stay reserved:
*/
#define PR_MPX_ENABLE_MANAGEMENT 43
#define PR_MPX_DISABLE_MANAGEMENT 44
diff --git a/kernel/sys.c b/kernel/sys.c
index a48cbf1..5fd7991 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -103,12 +103,6 @@
#ifndef SET_TSC_CTL
# define SET_TSC_CTL(a) (-EINVAL)
#endif
-#ifndef MPX_ENABLE_MANAGEMENT
-# define MPX_ENABLE_MANAGEMENT() (-EINVAL)
-#endif
-#ifndef MPX_DISABLE_MANAGEMENT
-# define MPX_DISABLE_MANAGEMENT() (-EINVAL)
-#endif
#ifndef GET_FP_MODE
# define GET_FP_MODE(a) (-EINVAL)
#endif
@@ -2448,15 +2442,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
up_write(&me->mm->mmap_sem);
break;
case PR_MPX_ENABLE_MANAGEMENT:
- if (arg2 || arg3 || arg4 || arg5)
- return -EINVAL;
- error = MPX_ENABLE_MANAGEMENT();
- break;
case PR_MPX_DISABLE_MANAGEMENT:
- if (arg2 || arg3 || arg4 || arg5)
- return -EINVAL;
- error = MPX_DISABLE_MANAGEMENT();
- break;
+ /* No longer implemented: */
+ return -EINVAL;
case PR_SET_FP_MODE:
error = SET_FP_MODE(me, arg2);
break;
--
2.7.4
